Add a comment briefly explaining why one timer tick is added to the watchdog delay. This has confused a lot of people and has resulted in numerous awkward discussions and ill-informed attempts to modify the code to remove that addition. Perhaps a rather lengthy comment will reduce that confusion and put an end to this thrashing.
In scene with CONFIG_SCHED_TICKLESS but no CONFIG_SCHED_TICKLESS_ALARM
The system may crash by assert
`up_assert: Assertion failed at file:wdog/wd_start.c line: 379 task: rptun`
Signed-off-by: zhuyanlin <zhuyanlin1@xiaomi.com>
when enable SYSTEM_TIME64, tick may exceed the int32 range
example:
pthread_cond_clockwait
---->clock_abstime2ticks
---->wd_start
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
If statement in line 103 could acces wdactivelist.head->lag when head was
NULL which could result in hard fault. The statement was also redundant
as the same condition is checked in the while loop below. This change
remove the if statement to prevent hard fault to occur.
Signed-off-by: Michal Lenc <michallenc@seznam.cz>
to save the preserved space(1KB) and also avoid the heap overhead
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I694073f68e1bd63960cedeea1ddec441437be025
* Simplify EINTR/ECANCEL error handling
1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx
* Unify the void cast usage
1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro
Squashed commit of the following:
Trivial, cosmetic
sched/, arch/, and include: Rename task_vforkstart() as nxtask_vforkstart()
sched/, arch/, and include: Rename task_vforkabort() as nxtask_vforkabort()
sched/, arch/, and include: Rename task_vforksetup() as nxtask_vfork_setup()
sched/: Rename notify_cancellation() as nxnotify_cancellation()
sched/: Rename task_recover() to nxtask_recover()
sched/task, sched/pthread/, Documentation/: Rename task_argsetup() and task_terminate() to nxtask_argsetup() and nxtask_terminate(), respectively.
sched/task: Rename task_schedsetup() to nxtask_schedsetup()
sched/ (plus some binfmt/, include/, and arch/): Rename task_start() and task_starthook() to nxtask_start() and nxtask_starthook().
arch/ and sched/: Rename task_exit() and task_exithook() to nxtask_exit() and nxtask_exithook(), respectively.
sched/task: Rename all internal, static, functions to begin with the nx prefix.
But certain logic interacts with tasks in different ways. The only one that comes to mind are wdogs. There is a tasking interface that to manipulate wdogs, and a different interface in the timer interrupt handling logic to manage wdog expirations.
In the normal case, this is fine. Since the tasking level code calls enter_critical_section, interrupts are disabled an no conflicts can occur. But that may not be the case in the SMP case. Most architectures do not permit disabling interrupts on other CPUs so enter_critical_section must work differently: Locks are required to protect code.
So this change adds locking (via enter_critical section) to wdog expiration logic for the the case if the SMP configuration.
